This invention relates to a communication and coding system for controlling electrical actuators. Electrical actuation members are currently controlled by remote command devices in various ways: by feeding a simple electrical signal to the load, as in the case of relays; by applying a phase signal to the appropriate input by a pushbutton, as in the case of lighting dimmers; and by using serial lines conveying digital signals, as in the case of particularly advanced actuators, which can also be connected to digital command buses. Each currently used control method however presents drawbacks and disadvantages for installers and final users. The most simple methods from the electrical viewpoint, i.e. controlling by a state signal or the temporary application of a phase signal by means of a pushbutton, do not allow large versatility in controllable functions, which remain limited to load switch-on and switch-off, and possibly dimmer adjustment for lighting devices.
Other methods involve feeding the electrical actuator with variable voltages or currents, which provide information regarding load switch-on or switch-off and offer the possibility of adjustment to intermediate control values, proportional to the fed voltage or current.
These method have however the drawback of not enabling (or at least only with great difficulty enabling) several command devices to be used, positioned in parallel and connected to the same actuator. The most complex methods, which also involve serial communication between control circuits and the electrical actuator, are reliable and can comprise many control devices connectable to a single actuator, but are extremely costly.
Hence, in none of the aforesaid cases used up to the present time is it possible to connect to one and the same actuator a multiplicity of different-type command devices of circuit complexity proportional to the functions to be performed, in a simple and economical manner.